ATO and AWC on a nano tank with Doser 2.1SA /Profilux 4

brief background to this question is: (still) preparing for a red sea reefer nano tank, and am looking for ways to automate the tank and reduce the role of caretakers (i.e. wife or friends/neighbors) during work trips (typically 4-8 days at a time, sometimes more) as much as possible.

the tank is anticipated to be mixed reef with some LPS/softies and a couple small fish, possibly an anemone.

i have been gradually arriving at using an aquarium controller for comfort, and focusing on the profilux for this role. I had not really thought about getting an automatic doser, but since i will have to get an ATO anyways (given the unreliability of the RSR's ATO system) and since it would be nice to automate water changes, i have been also considering using a doser 2.1 to do daily water changes (probably ~1g/day) and act as the ATO, in addition to possibly dosing for alk or whatever i need (still have not decided on what water to use, as there is a LFS about 10 steps away from my home, and that might make obtaining smallish amounts of water from them on a regular basis an interesting option).

does this seem like a wise move? the AWC load with around 1g/day does not seem to be too much, but i understand a doser isn't really designed for this over the long term, so looking for insight there. economically i'm also not so sure - would probably otherwise go for an osmolator and just do water changes and dosing manually, but if i could save the cost of the osmolator that might be better...

the other question would be: more sensible to go for the P4 and the SA or save a few on the slave unit? not sure if the meagre savings on the slave makes it worthwhile to sacrifice the flexibility...

I believe @d2mini currently runs a GHL 2.1 doser for his AWC set up, not sure if it's a slave or not but it's on a much larger system than yours and he seems reallt happy with it so I'm sure it would handle it no problem...

The 2.1 has heavy duty heads and will work great for you.
I use it on my 120g tank's daily auto water changes, changing out about 2.25g per day. It runs 150x per day if I remember correctly.
It's only running for about a minute each time so that's nothing for these motors.

If you already have the P4 or are planning on getting it, you can just get the slave unit.
The SA does offer a lot of extra features for just a little more but you'll have to decide if you'll actually use them if you have the P4, too.

As someone who also has to travel frequently for business, I wouldn't be without my GHL to manage the tank while I'm away.

Personally I wouldn't use the doser for ATO. I would just get a level sensor and a standard pump to operate from your RO reservoir. Most tanks should survive a couple of weeks without a water change, so I wouldn't worry about AWC via a doser.